hello Nordic
i am working with nrf52840, sdk 16.0
i am building my project over the peripheral app_ble_blinky example
i whish to have 2 seprate configs for saadc
i call the following init function twice (with 2 different saadc_configs (different naming as well) ):
err_code = nrf_drv_saadc_init(&saadc_config, saadc_sample_event_handler);
APP_ERROR_CHECK(err_code);
it does not seem to be working.. is there a way to initialize 2 saadc configs
best regards
Ziv
No, you have to uninit the driver beforehand.
What is it that you are trying to do exactly?
No, you have to uninit the driver beforehand.
ok .. i found out that saadc has bass address in the instantiation table, so to my understanding there can be only one operational 'nrf_drv_saadc_config_t' at a time, so it brings the question of how is it possible to read all the AIN0-7 channels when one instance can have only 4 channels if i am not wrong.
anyway, so i configure one 'nrf_drv_saadc_config_t' lets call 1_saadc_config and configure a second 'nrf_drv_saadc_config_t' 2_saadc_config,
then i call for nrf_drv_saadc_init(&1_saadc_config,... some handler)
then when sampling is done i call nrf_dev_saadc_uninit();
then i call for nrf_drv_saadc_init(&2_saadc_config, .. some other handler)
and when sampling is done i call nrf_drv_saadc_uninit();
i do not re-init the channel or try to convert the buffers again
i did not test it yet but i hope you can concur the above logic
What is it that you are trying to do exactly?
i need to read 2 analog inputs, each at a different time in the program's flow, so there is no collision there. each analog read requires different configurations in resolution and oversampling.
hope to read from you soon
best regards
Ziv
Hi,
It may be easier to just have only one buffer at any time, so:
1. First init by saadc_init()
2. Prepare buffer by nrf_drv_saadc_buffer_convert()
3. Then at some time in future execute sample by nrf_drv_saadc_sample()
4. Wait for NRF_DRV_SAADC_EVT_DONE event and handle saadc data
5. Prepare buffer by nrf_drv_saadc_buffer_convert()
Repeat from 3.
If you want to change saadc configuration, then uninit saadc and re-init saadc again, but make sure you clear potential adc channels that may have been used earlier. Also make sure you don't do this between step 3 and 4 above.
If you do any calibration of the saadc this should be done between 4 and 5 due to an errata, or between step 1 and 2.
You are right that oversampling can only be done if 1 channel is configured, this is a hardware limitation, so don't have any good workaround here; you could just sample the channels faster and discard those measurement that you don't want.
Best regards,
Kenneth
Hi Kenneth
sorry to say but this is not very clear and does not seem to help
my main hold back at the moment is that moving from debugging in release mode back to debug mode bring up all sort of assertions, one of them which currently holds me back is this one:
// Oversampling can be used only with one channel.
NRFX_ASSERT((nrf_saadc_oversample_get() != NRF_SAADC_OVERSAMPLE_DISABLED) ||
(m_cb.active_channels == 0));
it says oversampling can be only when working with one channel but if over sampling is disabled and i have more then one channel it asserts .. so what should i do???
after we can figure out why this is happening and how to fix it i will continue with other issues
basically just to remind, i use 2 saadc instances at different times in the program, each has its own definitions and its own channels (with different numbers for each channels - there is no overlapping there)
i init each of the saadc and its channels and then its buffers every time i wish to sample them and then uninit the saadc and reinit the other saadc and its channels and convert the buffers (each saadc has its own buffers)
hope you can help me and that my problem is better understood now
hope to read you soon
best regards
Ziv
I can't see from your code where you are calling nrf_drv_saadc_channel_uninit() for previous configured channels?
In hardware there is only one SAADC instance, so you will need to manually disable all ADC channels that is no longer in use. I do not think the uninit function of the driver does this for you.
Edit: Looking at nrfx_saadc_uninit() I can see this is done. Will need to look at this closer then.
Edit2:It doesn't make any sense that this should assert:
// Oversampling can be used only with one channel.
NRFX_ASSERT((nrf_saadc_oversample_get() != NRF_SAADC_OVERSAMPLE_DISABLED) ||
(m_cb.active_channels == 0));
Both these are cleared during nrf_drv_saadc_init()->nrfx_saadc_init() by:
nrf_saadc_oversample_set(p_config->oversample);
m_cb.active_channels = 0;
Are you 100% sure that p_config->oversample is false when calling nrfx_saadc_init()?
Kenneth
Are you 100% sure that p_config->oversample is false when calling nrfx_saadc_init()?
this assertion does not happen in the saadc init function, it happens when i try to init the second channel
1. i init saadc_1
2. int saadc_1 channels
3. convert buffers
4. sample
5. un-init saadc
6. init saadc_2
7. init saadc_2 channels -> here first channel init goes fine, in the second channel init i get the assertion
Are you 100% sure that p_config->oversample is false when calling nrfx_saadc_init()?
this assertion does not happen in the saadc init function, it happens when i try to init the second channel
1. i init saadc_1
2. int saadc_1 channels
3. convert buffers
4. sample
5. un-init saadc
6. init saadc_2
7. init saadc_2 channels -> here first channel init goes fine, in the second channel init i get the assertion
I understand that the assertion does not occur in saadc init function, however the values that is checked in NRFX_ASSERT() when channel init, is set during saadc init.
Hope that make sense,
Kenneth
yes the oversampling is something related to saadc init but as can be seen in my configurations:
//Configure SAADC
audio_saadc_config.resolution = NRF_SAADC_RESOLUTION_14BIT; //Set SAADC resolution to 12-bit. This will make the SAADC output values from 0 (when input voltage is 0V) to 2^12=2048 (when input voltage is 3.6V for channel gain setting of 1/6).
audio_saadc_config.oversample = NRF_SAADC_OVERSAMPLE_DISABLED; //DIABLED - //Set oversample to 4x. This will make the SAADC output a single averaged value when the SAMPLE task is triggered 4 times.
audio_saadc_config.interrupt_priority = APP_IRQ_PRIORITY_LOW; //Set SAADC interrupt to low priority.
audio_saadc_config.low_power_mode = NRFX_SAADC_CONFIG_LP_MODE;
the oversampling is disabled
still i get this assertion.. does it has anything to to with the previous configuration ?
if not then any idea for solving the problem ?
i will also add, maybe it matters, this 2 variables that one of them goes in the saadc init are global variables in each of the modules using the saadc
static nrf_drv_saadc_config_t audio_saadc_config; static nrf_saadc_channel_config_t audio_channel_config;
static nrf_drv_saadc_config_t hydr_saadc_config; static nrf_saadc_channel_config_t hydr_channel_config;
best regards
Ziv
Hi,
Are you able to find which of the two are causing the assert in the first place?
NRFX_ASSERT(nrf_saadc_oversample_get() != NRF_SAADC_OVERSAMPLE_DISABLED);
NRFX_ASSERT(m_cb.active_channels == 0);
Are you able to make a simple example where you switch between the two that I can run on an nRF52840-DK?
Kenneth
hi
in debug i can see the following:
nrf_saadc_oversample_get() = NRF_SAADC_OVERSAMPLE_DISABLED
m_cb.active_channels = 1
i can't understand the logic in that assertion .. it is saying the "Oversampling can be used only with one channel" but when over sampling is disabled it fails to, so what's the point ????
Are you able to make a simple example where you switch between the two that I can run on an nRF52840-DK?
i am not sure what you meant but i can't bring my self to write a code for testing on your side, i am on tight schedule and i am late cause of this unclear bug that i am trying to explain for so long.
here is all relevant saadc code in the order it is called:
global vars:
static nrf_drv_saadc_config_t audio_saadc_config;
static nrf_saadc_channel_config_t audio_channel_config;
static nrf_saadc_value_t m_buffer_pool[2][CONVERTED_ADC_SAMPELS_BUFF_SIZE];
static nrf_drv_saadc_config_t hydr_saadc_config;
static nrf_saadc_channel_config_t hydr_channel_config;
static nrf_saadc_value_t hydr_buffer_pool[HYDR_NUMBER_OF_ADC_SAMPLES];
relevant defins:
#define ADC_PIEZO_CHANNEL 0
#define ADC_MIC_CHANNEL 1
#define ADC_AMPLIFIER_CHANNEL 2
#define ADC_HYDRATION_CHANNEL 3
init calls:
Audio_sens_init();
Physical_measures_init();
the init themselvs:
void Audio_sens_init(void)
{
ret_code_t err_code;
// nrf_gpio_cfg_output(ARDUINO_13_PIN); // FOR DEBUG
//Configure SAADC
audio_saadc_config.resolution = NRF_SAADC_RESOLUTION_14BIT; //Set SAADC resolution to 12-bit. This will make the SAADC output values from 0 (when input voltage is 0V) to 2^12=2048 (when input voltage is 3.6V for channel gain setting of 1/6).
audio_saadc_config.oversample = NRF_SAADC_OVERSAMPLE_DISABLED; //DIABLED - //Set oversample to 4x. This will make the SAADC output a single averaged value when the SAMPLE task is triggered 4 times.
audio_saadc_config.interrupt_priority = APP_IRQ_PRIORITY_LOW; //Set SAADC interrupt to low priority.
audio_saadc_config.low_power_mode = NRFX_SAADC_CONFIG_LP_MODE;
//Configure SAADC channels:
audio_channel_config.reference = NRF_SAADC_REFERENCE_VDD4; //Set internal reference of fixed 0.6 volts
audio_channel_config.gain = NRF_SAADC_GAIN1_4; //Set input gain to 1/6. The maximum SAADC input voltage is then 0.6V/(1/6)=3.6V. The single ended input range is then 0V-3.6V
audio_channel_config.acq_time = NRF_SAADC_ACQTIME_10US; //Set acquisition time. Set low acquisition time to enable maximum sampling frequency of 200kHz. Set high acquisition time to allow maximum source resistance up to 800 kohm, see the SAADC electrical specification in the PS.
audio_channel_config.mode = NRF_SAADC_MODE_SINGLE_ENDED; //Set SAADC as single ended. This means it will only have the positive pin as input, and the negative pin is shorted to ground (0V) internally.
audio_channel_config.pin_n = NRF_SAADC_INPUT_DISABLED; //Since the SAADC is single ended, the negative pin is disabled. The negative pin is shorted to ground internally.
audio_channel_config.resistor_p = NRF_SAADC_RESISTOR_DISABLED; //Disable pullup resistor on the input pin
audio_channel_config.resistor_n = NRF_SAADC_RESISTOR_DISABLED;
audio_channel_config.burst = NRF_SAADC_BURST_DISABLED;
....(not relevant to saadc)
uint32_t saadc_sample_task_addr = nrf_drv_saadc_sample_task_get();
// samling event configurations - ppi timer event to start saadc sampling:
err_code = nrf_drv_ppi_channel_alloc(&m_ppi_channel);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_ppi_channel_assign(m_ppi_channel, timer_compare_event_addr, saadc_sample_task_addr);
APP_ERROR_CHECK(err_code);
....(not relevant to saadc)
}
void Physical_measures_init(void)
{
....(not relevant to saadc)
// init saadc read:
////////////////////////////
//Configure SAADC
hydr_saadc_config.resolution = NRF_SAADC_RESOLUTION_14BIT; //Set SAADC resolution to 12-bit. This will make the SAADC output values from 0 (when input voltage is 0V) to 2^12=2048 (when input voltage is 3.6V for channel gain setting of 1/6).
hydr_saadc_config.oversample = NRF_SAADC_OVERSAMPLE_4X; //Set oversample to 4x. This will make the SAADC output a single averaged value when the SAMPLE task is triggered 4 times.
hydr_saadc_config.interrupt_priority = APP_IRQ_PRIORITY_LOW; //Set SAADC interrupt to low priority.
hydr_saadc_config.low_power_mode = NRFX_SAADC_CONFIG_LP_MODE;
//Configure SAADC channel
hydr_channel_config.reference = NRF_SAADC_REFERENCE_VDD4; //Set internal reference of fixed 0.6 volts
hydr_channel_config.gain = NRF_SAADC_GAIN1_4; //Set input gain to 1/6. The maximum SAADC input voltage is then 0.6V/(1/6)=3.6V. The single ended input range is then 0V-3.6V
hydr_channel_config.acq_time = NRF_SAADC_ACQTIME_10US; //Set acquisition time. Set low acquisition time to enable maximum sampling frequency of 200kHz. Set high acquisition time to allow maximum source resistance up to 800 kohm, see the SAADC electrical specification in the PS.
hydr_channel_config.mode = NRF_SAADC_MODE_SINGLE_ENDED; //Set SAADC as single ended. This means it will only have the positive pin as input, and the negative pin is shorted to ground (0V) internally.
hydr_channel_config.pin_p = HYDRATION_ADC_INPUT_PIN; // adc input pin
hydr_channel_config.pin_n = NRF_SAADC_INPUT_DISABLED; //Since the SAADC is single ended, the negative pin is disabled. The negative pin is shorted to ground internally.
hydr_channel_config.resistor_p = NRF_SAADC_RESISTOR_DISABLED; //Disable pullup resistor on the input pin
hydr_channel_config.resistor_n = NRF_SAADC_RESISTOR_DISABLED;
hydr_channel_config.burst = NRF_SAADC_BURST_ENABLED;
}
saadc init calls in main loop (after initialization):
//Initialize SAADC
err_code = nrf_drv_saadc_init(&hydr_saadc_config, hydr_saadc_callback);
APP_ERROR_CHECK(err_code);
//Initialize SAADC channel
err_code = nrf_drv_saadc_channel_init(ADC_HYDRATION_CHANNEL, &hydr_channel_config);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_buffer_convert(hydr_buffer_pool, HYDR_NUMBER_OF_ADC_SAMPLES);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_sample(); // i want sampling to start only when i use saadc sample
APP_ERROR_CHECK(err_code);
static void hydr_saadc_callback(nrf_drv_saadc_evt_t const * p_event)
{
if (p_event->type == NRF_DRV_SAADC_EVT_DONE)
{
ret_code_t err_code;
// err_code = nrf_drv_saadc_buffer_convert(p_event->data.done.p_buffer, HYDR_NUMBER_OF_ADC_SAMPLES);
// APP_ERROR_CHECK(err_code);
hydration_sample_buff[count_of_10_min_sample_events] /*hydr_val*/ = p_event->data.done.p_buffer[0];// + p_event->data.done.p_buffer[1] + p_event->data.done.p_buffer[2] + p_event->data.done.p_buffer[3])/4;
measurments_state = MEASURE_STATE_DONE;
nrf_drv_saadc_uninit();
}
}
//Initialize second SAADC
err_code = nrf_drv_saadc_init(&audio_saadc_config, audio_saadc_callback);
APP_ERROR_CHECK(err_code);
audio_channel_config.pin_p = AUDIO_PIEZO_ADC_INPUT_PIN;
err_code = nrf_drv_saadc_channel_init(ADC_PIEZO_CHANNEL, &audio_channel_config);
APP_ERROR_CHECK(err_code);
audio_channel_config.pin_p = AUDIO_MIC_ADC_INPUT_PIN;
err_code = nrf_drv_saadc_channel_init(ADC_MIC_CHANNEL, &audio_channel_config);
///////
HERE IS WERE THE ASSERTION HAPPENS !!! IN THE CHANNEL INIT FOR ADC_MIC_CHANNEL
//////
APP_ERROR_CHECK(err_code);
audio_channel_config.pin_p = AUDIO_PIEZO_ADC_INPUT_PREAMPLYFIER_INPUT_PIN;
err_code = nrf_drv_saadc_channel_init(ADC_AMPLIFIER_CHANNEL, &audio_channel_config);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[0], CONVERTED_ADC_SAMPELS_BUFF_SIZE);
APP_ERROR_CHECK(err_code);
err_code = nrf_drv_saadc_buffer_convert(m_buffer_pool[1], CONVERTED_ADC_SAMPELS_BUFF_SIZE);
APP_ERROR_CHECK(err_code);
hope you can help me to solve this issue
best regards
Ziv
I think the best and fastest way forward is to send me a project that I can compile and run here on an nRF52840-DK to recreate this. Then I will be able to help you properly.
Best regards,
Kenneth